FIGS. 1 and 2 illustrate a conventional lead acid battery 100. In the conventional battery 100, cells of battery plates 110 are positioned in a battery housing 160. Tabs 111 protrude vertically from a top surface of the battery plates 110, and a lead strap 120 encompasses the tabs 111 of a cell of battery plates 110. A vertical tombstone 130 is positioned at an end of the lead strap 120, and forms a cell-to-cell connection by contacting a lead strap 120 of an adjacent cell of battery plates 110. A round terminal post 140 is positioned at a center of the end lead strap 120 and extends upward through a cover 150, to serve as an external terminal.
The lead straps 120 of a conventional lead acid battery 100 are formed using a steel cast-on mold with the shapes of the lead straps 120, tombstone 130, and terminal post 140 pre-formed therein. The cast-on mold is filled with molten lead, and the cell of battery plates 110 is inverted so that the tabs 111 are immersed in the molten lead. The cast-on mold is cooled, and the lead freezes, encapsulating the tabs 111 of the cell of battery plates 110. The cell of battery plates 110, lead strap 120, tombstone 130, and terminal post 140 are then ejected from the cast-on mold to form a group. Tombstone holes are punched into the battery housing 160 to correspond with the location of the tombstone 130, and the group is re-inverted and placed in the battery housing 160. The tombstone 130 of the group is positioned over the tombstone hole and is welded to the tombstone 130 of an opposing tombstone 130 of an adjacently positioned group. The cover 150 is heat sealed to the battery housing 160 with the terminal post 140 extending through and out of the cover 150.
The conventional lead acid battery 100 has a number of drawbacks. For example, the use of the vertical tombstone 130 restricts the vertical height of the cell of battery plates 110 in the housing 160. This restricts the amount of energy available in the same size battery housing 160. Further, the additional step of punching out the tombstone holes and the welding together of adjacent tombstones 130 increases the manufacturing steps and cost of production. A lead acid battery design that reduces the height, or completely eliminates the tombstone 130 would allow the height of the cells of battery plates 110 to be increased, providing more energy in the same sized battery housing 160.